Certain operations of an assembly line, such as resistance welding operations, require the automatic transportation and positioning of certain parts, such as pipe couplers, that have open internal geometries onto a workpiece. Typically, such parts are transported using a vacuum that holds the parts in place in the tip of the vacuum tube. The vacuum is constantly maintained on the part until it is correctly positioned onto the workpiece.
This method, however, requires expensive equipment, such as vacuum pumps and piping, to draw sufficient vacuum on the part. The piping along the line must be monitored continuously to ensure that there is no loss of vacuum pressure due to leaks throughout the system. To maintain the vacuum, pump motors need to be running for extensive periods of time during the operation. This increases the heat and wear on the pump motors and could lead to malfunctioning. Thus, the use of vacuum increases maintenance costs for the assembly line and is often a source of downtime due to system leaks and failures of vacuum pump motors. Additionally, the geometry of the part is critical because the vacuum can be lost due to variations in the part dimensions. This increases the cost of such parts because tighter tolerances must be maintained.